ground.RdExtract ground layer from VoxelSpace object.
The ground layer is the set of voxels that are just above ground level. The
bottom facet of the voxel must be above ground
ground_distance(voxel_center) >= dz/2 with dz the voxel size on z axis.
Ground layer may be missing (the function returns an empty data.table) or
incomplete (the function returns a data.table with
nrow(ground(vxsp)) < prod(dim(vxsp)[1:2])) for some voxel space.
Function aboveGround returns voxel index above ground layer (included).
Function belowGround returns voxel index below ground layer (excluded).
ground(vxsp)
belowGround(vxsp)
aboveGround(vxsp)
groundEnergy(vxsp)
groundElevation(vxsp)a VoxelSpace object.
data.table::data.table object with voxel index either
below ground, ground level or above ground.
vxsp <- readVoxelSpace(system.file("extdata", "tls_sample.vox", package = "AMAPVox"))
gr <- ground(vxsp)
ag <- aboveGround(vxsp)
bg <- belowGround(vxsp) # empty in test case
# ground layer included in above ground subset
all(ag[gr, on=list(i, j, k)] == gr) # TRUE expected
#> [1] TRUE
vxsp@data[ag, on=list(i, j, k)]
#> i j k ground_distance nbEchos nbSampling lgTotal lMeanTotal
#> <int> <int> <int> <num> <int> <int> <num> <num>
#> 1: 0 0 0 0.25 0 3369 1100.3662 0.3266151
#> 2: 0 0 1 0.75 0 3129 904.9130 0.2892020
#> 3: 0 0 2 1.25 0 2406 751.1223 0.3121872
#> 4: 0 0 3 1.75 0 2106 659.1803 0.3130011
#> 5: 0 0 4 2.25 0 1919 602.4054 0.3139163
#> ---
#> 416: 6 5 5 2.75 0 1533 495.9831 0.3235376
#> 417: 6 5 6 3.25 0 1394 458.5256 0.3289280
#> 418: 6 5 7 3.75 0 1261 422.9537 0.3354113
#> 419: 6 5 8 4.25 0 823 283.2120 0.3441215
#> 420: 6 5 9 4.75 0 813 288.8458 0.3552839
#> sdLength angleMean bsPotential bsEntering bsIntercepted transmittance
#> <num> <num> <num> <num> <num> <num>
#> 1: 0.1866441 68.74669 0.18236696 0.18164480 0 1
#> 2: 0.1943504 61.30513 0.17215119 0.17109131 0 1
#> 3: 0.1980757 54.47612 0.13515397 0.13368462 0 1
#> 4: 0.1985490 52.09007 0.12226181 0.12128547 0 1
#> 5: 0.1975347 51.82097 0.11477382 0.11332583 0 1
#> ---
#> 416: 0.1947745 51.03537 0.09570192 0.09483800 0 1
#> 417: 0.1926026 52.84722 0.08968004 0.08821365 0 1
#> 418: 0.1887876 54.56818 0.08480823 0.08081702 0 1
#> 419: 0.1861656 71.59585 0.06110164 0.05498709 0 1
#> 420: 0.1826305 72.38877 0.06070402 0.05445548 0 1
#> PadBVTotal attenuation_FPL_biasedMLE attenuation_FPL_biasCorrection
#> <num> <num> <num>
#> 1: 0 0 0
#> 2: 0 0 0
#> 3: 0 0 0
#> 4: 0 0 0
#> 5: 0 0 0
#> ---
#> 416: 0 0 0
#> 417: 0 0 0
#> 418: 0 0 0
#> 419: 0 0 0
#> 420: 0 0 0
#> attenuation_FPL_unbiasedMLE weightedEffectiveFreepathLength
#> <num> <num>
#> 1: 0 0.05982848
#> 2: 0 0.04976479
#> 3: 0 0.04226232
#> 4: 0 0.03827859
#> 5: 0 0.03578283
#> ---
#> 416: 0 0.03092307
#> 417: 0 0.02917568
#> 418: 0 0.02708526
#> 419: 0 0.01887177
#> 420: 0 0.01926193
#> weightedFreepathLength attenuation_PPL_MLE distLaser
#> <num> <num> <num>
#> 1: 0.05956666 0 3.585220
#> 2: 0.04955374 0 3.768980
#> 3: 0.04207453 0 3.980582
#> 4: 0.03810857 0 4.410619
#> 5: 0.03562487 0 4.757694
#> ---
#> 416: 0.03078603 0 5.328756
#> 417: 0.02904613 0 5.649271
#> 418: 0.02696477 0 5.863010
#> 419: 0.01878658 0 6.421073
#> 420: 0.01917410 0 6.466489